Chemical detection of substances by utilizing a sample medium impregnated with solid test chemicals

ABSTRACT

In some embodiments, the present disclosure pertains to substance detecting assemblies that include: (1) a sample medium (e.g., filter paper); and (2) a solid test chemical (e.g., zinc) impregnated with the sample medium. In some embodiments, the present disclosure pertains to methods of making an assembly for detecting a substance by: (1) providing a sample medium; (2) providing a solid test chemical; and (3) impregnating the sample medium with the solid test chemical. In further embodiments, the present disclosure pertains to methods for detecting a substance by: (1) collecting the substance on a sample medium that is impregnated with a solid test chemical; and (2) initiating a reaction of the substance with the solid test chemical on the sample medium to generate a color that corresponds to the substance. In some embodiments, the sample medium is then inserted into a chemical detection unit for the detection of the substance.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/776,967, filed on Sep. 15, 2015, which is a U.S. National StageApplication of International Patent Application No. PCT/US2014/030467,filed on Mar. 17, 2014, which claims priority to U.S. Provisional PatentApplication No. 61/800,177, filed on Mar. 15, 2013. The entirety of eachof the aforementioned applications is incorporated herein by reference.

This application is related to U.S. patent application Ser. No.12/309,704, filed on Jan. 26, 2009, now U.S. Pat. No. 8,980,641;PCT/US2013/032603, filed on Mar. 15, 2013; and U.S. patent applicationSer. No. 29/475,778, filed on Dec. 6, 2013, now U.S. D727762. Theentirety of each of the aforementioned applications is also incorporatedherein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

Not applicable.

BACKGROUND

Methods and systems for the trace detection of various substances (e.g.,drugs and explosives) suffer from numerous limitations. Such limitationsinclude efficacy, sensitivity, and the availability of test chemicals.Various embodiments of the present disclosure address these limitations.

SUMMARY

In some embodiments, the present disclosure pertains to assemblies fordetecting a substance. In some embodiments, the assemblies include: (1)a sample medium; and (2) a solid test chemical that is impregnated withthe sample medium. In some embodiments, the solid test chemical isdispersed on a surface of the sample medium. In some embodiments, thesolid test chemical is selected from the group consisting of metals,transition metals, metalloids, and combinations thereof. In someembodiments, the solid test chemical is zinc.

In some embodiments, the sample medium is selected from the groupconsisting of filter papers, porous sheets of fibers, porous papers, andcombinations thereof. In some embodiments, the sample medium comprises apad of a flexible card component that can be inserted into a chemicaldetection unit.

Additional embodiments of the present disclosure pertain to methods ofmaking an assembly for detecting a substance. In some embodiments, suchmethods comprise: (1) providing a sample medium; (2) providing a solidtest chemical; and (3) impregnating the sample medium with the solidtest chemical. In some embodiments, the impregnating occurs by: (1)suspending the solid test chemical in a solvent to form a suspension;(2) applying the suspension onto the sample medium; and (3) allowing thesolvent to evaporate.

In further embodiments, the present disclosure pertains to methods fordetecting a substance by: (1) collecting the substance on a samplemedium that is impregnated with a solid test chemical; and (2)initiating a reaction of the substance with the solid test chemical onthe sample medium to generate a color that corresponds to the substance.

In some embodiments, the substance to be detected is selected from thegroup consisting of biohazards, toxins, radioactive materials,narcotics, explosives, and combinations thereof. In some embodiments,the substance to be detected includes one or more explosives, such asnitroaromatics, nitrate esters, nitramines, inorganic nitrates,chlorates, peroxides, perchlorates, and combinations thereof.

In some embodiments, the solid test chemical is zinc, and the substanceto be detected is an inorganic nitrate. In some embodiments, the zincreacts with the inorganic nitrate to produce nitrite ions. The nitriteions can then undergo a subsequent reaction (e.g., a Greiss reaction) togenerate a color.

In some embodiments, the substance is collected on the sample medium byswiping the sample medium onto a surface containing the substance. Insome embodiments, the sample medium is a pad of a flexible cardcomponent that is subsequently inserted into a chemical detection unitfor automatic colorimetric detection of the substance.

DESCRIPTION OF THE FIGURES

FIG. 1 provides images of a sample medium in various contexts. FIG. 1Aprovides an image of a sample medium 10 that is impregnated with solidtest chemicals. FIG. 1B provides an image of sample medium 10 as part offlexible card component 12. FIG. 1C provides an image of the variousparts of flexible card component 12.

FIG. 2 provides a scheme for the use of a sample medium for detectingsubstances.

FIG. 3 provides an image of a chemical detection unit that can beutilized to detect substances on a sample medium.

DETAILED DESCRIPTION

It is to be understood that both the foregoing general description andthe following detailed description are illustrative and explanatory, andare not restrictive of the subject matter, as claimed. In thisapplication, the use of the singular includes the plural, the word “a”or “an” means “at least one”, and the use of “or” means “and/or”, unlessspecifically stated otherwise. Furthermore, the use of the term“including”, as well as other forms, such as “includes” and “included”,is not limiting. Also, terms such as “element” or “component” encompassboth elements or components comprising one unit and elements orcomponents that comprise more than one unit unless specifically statedotherwise.

The section headings used herein are for organizational purposes and arenot to be construed as limiting the subject matter described. Alldocuments, or portions of documents, cited in this application,including, but not limited to, patents, patent applications, articles,books, and treatises, are hereby expressly incorporated herein byreference in their entirety for any purpose. In the event that one ormore of the incorporated literature and similar materials defines a termin a manner that contradicts the definition of that term in thisapplication, this application controls.

Chemical detection systems and methods are known to be useful fordetecting various substances, such as explosives and drugs. In manyinstances, chemical detection systems and methods involve use of testchemicals that react with the substance to produce a measurable orobservable product for detection of the substance. For example,colorimetric chemical detection systems and methods detect the substanceby producing a colored product for detection of the substance.Conventional detection methods and systems tend to use suspension of thetest chemicals in a liquid.

For detection of some substances, it is desirable to have solids ormetals involved in a chemical reaction. For example, zinc is known toreact with inorganic nitrates to reduce them to nitrite ions that reactwith further test chemical for detection. For example, the Griessreaction is well-known for producing a colored azo dye from reaction oftest chemicals with nitrite ions. However, zinc is not soluble inliquids. Therefore, it is suspended in suitable solvents forcolorimetric testing.

Nonetheless, a difficulty arises in getting insoluble solids to mix wellin solution. More particularly, it tends to be difficult to be able tokeep the solids suspended without constant stirring. Furthermore, anydispensing of the solid in solution is challenging due to the dispensingmethod used.

Therefore, there remains a need for systems and processes through whichto utilize solid test chemicals efficiently and effectively. Moreparticularly, various methods and systems are desirable to allow solidtest chemicals to interact with various substances without the need tosuspend them in a liquid.

In some embodiments, the present disclosure pertains to assemblies thatare impregnated with solid test chemicals for detecting varioussubstances. In some embodiments, the present disclosure pertains tomethods of making such assemblies. In some embodiments, the presentdisclosure pertains to using such assemblies for detecting substances.

Detection Assemblies

In some embodiments, the present disclosure pertains to assemblies fordetecting various substances. In some embodiments that are described inmore detail herein, the substances to be detected include, withoutlimitation, biohazards, toxins, radioactive materials, narcotics,explosives, and combinations thereof.

In some embodiments, the assemblies include a sample medium that isimpregnated with a solid test chemical. As set forth in more detailherein, the detection assemblies of the present disclosure can includevarious sample media and solid test chemicals.

Sample Media

A sample medium generally refers to a region, structure or systemcomponent that can be used to detect a substance. In some embodiments,the sample medium includes, without limitation, filter papers, poroussheets of fibers, porous papers, and combinations thereof. In someembodiments, the sample medium is a filter paper. Various types ofmaterials may also be used as sample media. For instance, in someembodiments, the materials in the sample medium include, withoutlimitation, papers, polyesters, cotton, plastics, and combinationsthereof. In more specific embodiments, the sample medium includes atleast one of a cotton-based filter paper, a polyester-based filterpaper, a plastic-based filter paper, and combinations thereof.

In some embodiments, the sample medium is in the form of a pad. Forinstance, in some embodiments, a sample medium is in the form of pad 10shown in FIG. 1A. In some embodiments, the sample medium is in the formof a pad of a flexible card component. For instance, in some embodimentsthat are shown in FIG. 1B, the sample medium is in the form of pad 10 onflexible card component 12.

In some embodiments, the sample medium may be in fluid communicationwith one or more liquid reagents. For instance, in some embodimentsshown in FIG. 1C, the sample medium may be in the form of pad 10 offlexible card component 12, where the flexible card component containstwo reagent releasable capsules 18 that are in fluid communication withpad 10. In this embodiment, flexible card component 12 also contains toplayer 14, inner layer 16, and bottom layer 20.

Additional structures for establishing fluid communication between asample medium and one or more liquid reagents can also be envisioned.For instance, in some embodiments, the sample media of the presentdisclosure may be used on the card pads described in U.S. patentapplication Ser. No. 12/309,704, filed on Jan. 26, 2009, now U.S. Pat.No. 8,980,641. In further embodiments, the sample media of the presentdisclosure may be utilized in the test areas described inPCT/US2013/032603.

Solid Test Chemicals

In some embodiments, the sample medium is associated with a solid testchemical. Solid test chemicals generally refer to materials that are insolid form and capable of reaction with a substance to be detected(e.g., explosives). Various solid test chemicals may be associated withsample media. For instance, in some embodiments, the solid test chemicalincludes, without limitation, metals, transition metals, metalloids, andcombinations thereof. In some embodiments, the solid test chemicalincludes, without limitation, nickel, titanium, vanadium, manganese,iron, cobalt, copper, zinc, molybdenum, gold, silver, and combinationsthereof. In some embodiments, the solid test chemical is zinc.

In some embodiments, the solid test chemical is insoluble in water. Insome embodiments, the solid test chemical is insoluble in varioussolvents, such as ethanol.

Solid test chemicals may be associated with sample media in variousmanners. For instance, in some embodiments the sample medium isimpregnated with a solid test chemical. In some embodiments, the solidtest chemical is dispersed on a surface of the sample medium. In someembodiments, the solid test chemical is localized on a selected regionof the sample medium. In some embodiments, the solid test chemical isdispersed uniformly on the surface of the sample medium.

Methods of Making Chemical Detection Assemblies

In some embodiments, the present disclosure pertains to methods ofmaking an assembly for detecting a substance. In some embodiments, theassembly methods include: (1) providing a sample medium; (2) providing asolid test chemical; and (3) impregnating the sample medium with thesolid test chemical. Various sample media and solid test chemicals (asdescribed previously) may be utilized for the aforementioned assemblymethods. Furthermore, various methods may be utilized to impregnatesample media with solid test chemicals.

Impregnating Sample Media with Solid Test Chemicals

In some embodiments, sample media are impregnated with solid testchemicals by applying solid test chemicals onto sample media. In someembodiments, the applying occurs by spraying, dropping, chemical vapordeposition, sputtering, and similar methods.

In more specific embodiments, sample media are impregnated with solidtest chemicals by: (1) suspending the solid test chemical in a solventto form a suspension; (2) applying the suspension onto the samplemedium; and (3) allowing the solvent to evaporate. In some embodiments,the suspending occurs by mixing the solid test chemical into a solvent.In some embodiments, the applying occurs by spraying the suspension ontothe sample medium. In some embodiments, the applying occurs by droppingthe suspension onto the sample medium. In some embodiments, the applyingincludes removing predetermined volumes from a continuously stirringsuspension and dropping the suspension onto the sample medium.

In some embodiments, the solvent is allowed to evaporate by incubationat room temperature. In some embodiments, the solvent is inert to thereaction between the solid test chemical and the substance. In someembodiments, the solvent includes, without limitation, ethanol,methanol, isopropyl alcohol, water, and combinations thereof. In someembodiments, the solvent is ethanol.

Methods of Detecting Substances

Additional embodiments of the present disclosure pertain to methods ofdetecting a substance by utilizing the sample media of the presentdisclosure. For instance, in some embodiment illustrated in FIG. 2, suchmethods include: collecting the substance on a sample medium that isimpregnated with a solid test chemical (step 12); and initiating areaction of the substance with the solid test chemical on the samplemedium (step 14) to generate a color that corresponds to the substance(step 16). In some embodiments, the methods of the present disclosurealso include one or more steps of detecting the color (step 18),matching the color to known substances (step 20), and/or detecting thesubstance (step 22).

As set forth in more detail herein, the methods of the presentdisclosure can have various embodiments. In particular, various testchemicals may be impregnated onto various sample media to react withvarious substances on the sample media. Furthermore, various methods maybe utilized to collect substances on sample media, initiate reactions,and generate colors.

In some embodiments, one or more of the aforementioned steps may occurin an automated and/or controlled manner. In some embodiments, one ormore of the aforementioned steps may occur by the utilization of achemical detection unit.

Sample Media

As set forth previously, the methods of the present disclosure mayutilize various sample media. In some embodiments, the sample mediumincludes, without limitation, filter papers, porous sheets of fibers,porous papers, and combinations thereof. In some embodiments, the samplemedium includes at least one of a cotton-based filter paper, apolyester-based filter paper, a plastic-based filter paper, andcombinations thereof.

In some embodiments, the sample medium is in the form of a pad, such aspad 10 shown in FIG. 1A. In some embodiments, the sample medium is inthe form of a pad of a flexible card component, such as pad 10 onflexible card component 12, as shown in FIG. 1B. In some embodiments,the sample medium may be in fluid communication with one or more liquidreagents, such as liquid reagents in reagent releasable capsules 18 offlexible card component 12, as shown in FIG. 1C.

Solid Test Chemicals

As set forth previously, various solid test chemicals may be impregnatedonto various sample media. In some embodiments, the solid test chemicalsare dispersed on a surface of a sample medium. In some embodiments, thesolid test chemicals include, without limitation, metals, transitionmetals, metalloids, and combinations thereof. In some embodiments, thesolid test chemical includes, without limitation, nickel, titanium,vanadium, manganese, iron, cobalt, copper, zinc, molybdenum, gold,silver, and combinations thereof. In some embodiments, the solid testchemicals may include zinc.

Substances

The methods of the present disclosure may be utilized to detect varioussubstances. In some embodiments, the substances may include, withoutlimitation, biohazards, toxins, radioactive materials, narcotics,explosives, and combinations thereof.

In some embodiments, the substance to be detected includes explosives.In some embodiments, the explosives include, without limitation,nitroaromatics, nitrate esters, nitramines, inorganic nitrates,chlorates, peroxides, perchlorates, and combinations thereof.

In some embodiments, the explosives include inorganic nitrates, such asammonium nitrate, urea nitrate, potassium nitrate, sodium nitrate, andthe like. In some embodiments, the explosives include nitroaromatics,such as TNT, TNB, DNT, DNB, Tetryl, and the like. In some embodiments,the explosives include nitrate esters and nitramines, such as HMX, RDX,PETN, Semtex, Nitroglycerin, EGDN, Pyrodex, and the like. In someembodiments, the explosives include chlorates, such as sodium chlorate,potassium chlorate, and the like. In some embodiments, the explosivesinclude peroxides, such as TATP, HMTD, and the like. The detection ofadditional explosives can also be envisioned.

In more specific embodiments, zinc is the solid test chemical and thesubstance is an inorganic nitrate. In further embodiments, zinc is usedas a solid test chemical to detect ammonium nitrate, urea nitrate,potassium, sodium nitrate, and combinations thereof.

In some embodiments, substances to be detected include narcotics. Insome embodiments, the narcotics include, without limitation, opiates,cocaine, methamphetamine, MDMA, ecstasy, THC, marijuana, ketamine, andcombinations thereof. In some embodiments, the narcotics includeopiates, such as heroin, morphine, codeine, and the like. The detectionof additional narcotics can also be envisioned.

Substances may be present on a sample medium in various amounts. Forinstance, in some embodiments, a substance may be present on a samplemedium in amounts ranging from about 10 ng to about 100 mg. In someembodiments, a substance may be present on a sample medium in amountsranging from about 100 ng to about 1 mg. In some embodiments, severalsubstances may be present on a sample medium in total amounts rangingfrom about 10 ng to about 100 mg. In some embodiments, severalsubstances may be present on a sample medium in total amounts rangingfrom about 100 ng to about 1 mg.

In addition, substances may be present on a sample medium in variousstates. For instance, in some embodiments, substances may be present ona sample medium in solid state, liquid state, gaseous state, orcombinations of such states. In some embodiments, substances may bepresent on a sample medium in a solid state. In some embodiments,substances may be present on a sample medium in a liquid state.

Collection of Substances

Various methods may also be utilized to collect substances on samplemedia. For instance, in some embodiments, a substance may be collectedon a sample medium by swiping the sample medium onto a surface thatcontains the substance. In some embodiments, a substance is collected ona sample medium by dropping a liquid containing the substance onto thesample medium. In some embodiments, a substance is collected on a samplemedium by exposing the sample medium to a gaseous environment containingthe substance. Additional methods of collecting substances on samplemedia can also be envisioned.

Reaction Initiation

Various methods may also be utilized to initiate a reaction of asubstance with a solid test chemical on a sample medium. In someembodiments, the reactions of substances with solid test chemicals maybe initiated manually. In some embodiments, the reactions of substanceswith solid test chemicals may be initiated in an automated and/orcontrolled fashion. In some embodiments, a chemical detection unit maybe utilized to initiate reactions of substances with solid testchemicals. Various aspects of such embodiments are described in moredetail herein

For instance, in some embodiments, the reaction may be initiated byincubating the sample medium that contains a substance and solid testchemical at room temperature. In some embodiments, the sample medium isincubated at room temperature for about 5 minutes to about 60 minutes.

In some embodiments, a reaction of a substance with a solid testchemical is initiated by applying one or more liquid reagents onto thesample medium. In some embodiments, a reaction is initiated by utilizinga flexible card component that includes a sample medium and at least oneliquid reagent in a reagent releasable capsule. For instance, in someembodiments where a substance is on pad 10 of flexible card component 12(FIG. 1C), liquid reagents from reagent releasable capsules 18 may beapplied to pad 10 in order to initiate the reaction of the substancewith a solid test chemical on pad 10.

In some embodiments, the reaction is initiated after coupling a samplemedium with a hand held chemical detection unit. In more specificembodiments shown in FIG. 3, a reaction is initiated by couplingflexible card component 12 that contains pad 10 with chemical detectionunit 100 through opening 30. The use of additional chemical detectionunits can also be envisioned. For instance, another chemical detectionunit suitable for use with the methods of the present disclosure isdisclosed in U.S. patent application Ser. No. 29/475,778, filed on Dec.6, 2013, now U.S. D727762.

In some embodiments, the coupling of a flexible card component with ahand held chemical detection unit causes a wall of a reagent releasablecapsule to yield to fluid flow to establish fluid communication betweena liquid reagent in the reagent releasable capsule and the pad. Forinstance, in some embodiments illustrated in FIGS. 1C and 3, thecoupling of flexible card component 12 with hand held chemical detectionunit 100 causes walls of reagent releasable capsules 18 to yield tofluid flow to establish fluid communication between liquid reagents inreagent releasable capsules 18 and pad 10.

In some embodiments, establishment of fluid communication between atleast one reagent releasable capsule and a pad can occur by a disruptionof a wall of the reagent releasable capsule upon the coupling of the padwith a hand held chemical detection unit. In some embodiments, thedisruption of the wall of the reagent releasable capsule occurs by atleast one of an application of pressure to the wall, an application ofheat to the wall, a mechanical breaking of the wall, a mechanicalpuncturing of the wall, or combinations thereof.

In some embodiments, the methods of the present disclosure also includea step of stimulating a reaction of a substance with a solid testchemical on a sample medium. In some embodiments, the stimulating occursafter initiating the reaction. In some embodiments, the stimulatingoccurs by heating the sample medium. In some embodiments, thestimulating occurs after applying one or more liquid reagents onto thesample medium.

In some embodiments, the stimulating occurs inside a hand held chemicaldetection unit, such as chemical detection unit 100 (FIG. 3). In someembodiments, the simulating generates a color that corresponds to thesubstance. In some embodiments, the stimulating includes an applicationof heat to the pad of a flexible card component (e.g., pad 10 offlexible card component 12, as shown in FIGS. 3 and 1A) to enhance thereaction.

Various liquid reagents may be utilized to initiate reactions ofsubstances with solid test chemicals. For instance, in some embodiments,the liquid reagents may include one or more solvents. In someembodiments, the solvents may include, without limitation, ethanol,methanol, isopropyl alcohol, toluene, hexanes, water, various alcohols,acetonitrile, and combinations thereof.

Various reactions of substances with solid test chemicals may occur. Insome embodiments, the solid test chemical serves as a reactant in areaction. In some embodiments, the solid test chemical serves as acatalyst in a reaction. In more embodiments where the solid testchemical is zinc and the substance is an inorganic nitrate (e.g.,ammonium nitrate, urea nitrate, potassium nitrate, sodium nitrate andcombinations thereof), the zinc reacts with the inorganic nitrate toproduce nitrite ions.

Generation of Color

In some embodiments, a color is generated upon the reaction of a solidtest chemical with a substance. In some embodiments, the color isgenerated as a direct result of the reaction of a solid test chemicalwith a substance. In some embodiments, the color is generated as anindirect result of the reaction of a solid test chemical with asubstance. For instance, in some embodiments, one or more additionalreactions after the reaction of the solid test chemical with a substancemay be required to generate a color. In a more specific embodiment wherezinc is the solid test chemical and the substance includes inorganicnitrates (e.g., ammonium nitrate, urea nitrate, potassium nitrate,sodium nitrate and combinations thereof), the zinc reacts with inorganicnitrates to reduce them to nitrite ions. Thereafter, the nitrite ionsreact with one or more liquid reagents (e.g., reagents from reagentreleasable capsules 18 shown in FIG. 1C) in a Griess reaction to producea colored azo dye.

In some embodiments, the generated color is derived from regions of thehuman visible spectrum, ultraviolet regions of the electromagneticspectrum, infrared regions of the electromagnetic spectrum, andcombinations thereof. In some embodiments, the generated color includesa change in color that is different form the solid test chemical and thesubstance. In some embodiments, the color includes a change in aspectral pattern of colors that is different from the spectral patternof colors of the solid test chemical and the substance.

Detection of Color

Various methods may be utilized to detect colors that are generated uponthe reaction of a solid test chemical with a substance. In someembodiments, the generated color may be detected visually by the nakedeye. In some embodiments, the generated color may be detected byutilizing an optical instrument. In some embodiments, the opticalinstrument may be in a hand held chemical detection unit, such aschemical detection unit 100 (FIG. 3). In some embodiments, the chemicaldetection unit may detect the color and store data related to the color.

In some embodiments, the chemical detection unit may contain an opticalinstrument that includes light emitting diodes and an optical sensor. Insome embodiments, the light emitting diodes illuminate the sample mediumwith various colors of light to allow for detection of a spectralpattern of colors by the optical sensor.

Matching of the Generated Color with Known Substances

Various methods may also be utilized to match colors generated from thereaction of a solid test chemical with a substance (i.e., generatedcolor) with known substances. For instance, in some embodiments, thematching occurs by matching the generated color with the generated colorof known substances in a database to determine the substance in thesample. In some embodiments, the matching occurs manually. In someembodiments, the matching occurs automatically. In more specificembodiments, the matching includes analyzing data (e.g., stored data)related to the generated color. In some embodiments, the matching occursby utilizing a comparison algorithm. In some embodiments, the matchingoccurs by analyzing data (e.g., stored data) related to the generatedcolor by utilizing a comparison algorithm.

In some embodiments, the matching occurs by comparing the generatedcolor to a certain color threshold value. In some embodiments, if thegenerated color exceeds the color threshold value, then a certainsubstance is detected (e.g., an explosive, such as an inorganicnitrate). However, if there generated color does not exceed the colorthreshold value, then the substance is not detected.

In some embodiments, the generated color is compared to a colorthreshold value by utilizing a color algorithm. In some embodiments, thecolor threshold value may include an algorithm that utilizes colormagnitude or intensity, rate of color change, decreasing color changeand timing of the various color changes.

In further embodiments, the methods of the present disclosure may alsoinclude a step of displaying detection results. For instance, in someembodiments, detection results are displayed on a display unit of a handheld chemical detection unit, such as chemical detection unit 100 (FIG.3).

Control of Reactions

In some embodiments, the methods of the present disclosure may alsoinclude one or more control steps over reaction conditions. Forinstance, in some embodiments, the initiating of the reaction isperformed in a controlled sequence of reactions with liquid reagents inat least a first reagent releasable capsule and a second reagentreleasable capsule (e.g., reagent releasable capsules 18, as shown inFIG. 1A), where the first reagent releasable capsule and the secondreagent releasable capsule are in fluid communication with the samplemedium (e.g., pad 10 on flexible card component 12, as also shown inFIG. 1A). In more specific embodiments, the initiating of the reactionis controlled by controlling flow times of the liquid reagents in thefirst and second reagent releasable capsules onto the sample medium. Forinstance, in some embodiments, the controlling includes controlling flowrates of the liquid reagents in the first and second reagent releasablecapsules onto the sample medium. In some embodiments, the controllingincludes controlling the arrival of the liquid reagents in the first andsecond reagent releasable capsules onto the sample medium. In someembodiments, the controlling results in the arrival of the liquidreagent in the first reagent releasable capsule onto the sample mediumprior to the arrival of the liquid reagent in the second reagentreleasable capsule onto the sample medium. In some embodiments, thecontrolling results in the arrival of the liquid reagent in the secondreagent releasable capsule onto the sample medium prior to the arrivalof the liquid reagent in the first reagent releasable capsule onto thesample medium. In some embodiments, the controlling results in thesimultaneous arrival of the liquid reagents in the first and secondreagent releasable capsules onto the sample medium. Additional methodsby which to control reaction conditions are described inPCT/US2013/032603.

Applications and Advantages

The methods and systems of the present disclosure allow for chemicalreactions to take place that involve insoluble test chemicals, such asinsoluble metals (e.g., zinc). Furthermore, the methods and systems ofthe present disclosure allow for the colorimetric detection of tracesubstances by utilizing such reactions.

To the best of Applicant's knowledge, the colorimetric detection oftrace substances by utilizing solid test chemicals that are impregnatedonto a sample medium has not been performed or deemed feasible.Moreover, such methods can be used for the automated detection ofvarious trace substances in various environments, such as the detectionof drugs and/or explosives at airports, public areas, and otherenvironments. In some embodiments, the methods and systems of thepresent disclosure may be utilized to detect trace amounts of substancesthat are present on a sample medium in amounts ranging from about 10 ngto about 100 mg. In some embodiments, the methods and systems of thepresent disclosure may be utilized to detect trace amounts of substancesthat are present on a sample medium in amounts ranging from about 100 ngto about 1 mg.

The systems and methods of the present disclosure are suitable for usewith various automated colorimetric detection systems. Examples ofautomated colorimetric detection systems are described in U.S. patentapplication Ser. No. 12/309,704, filed on Jan. 26, 2009, now U.S. Pat.No. 8,980,641; and PCT/US2013/032603, filed on Mar. 15, 2013. Forinstance, in some embodiments, the sample media of the presentdisclosure may be used on the card pads described in U.S. patentapplication Ser. No. 12/309,704, filed on Jan. 26, 2009, now U.S. Pat.No. 8,980,641. In further embodiments, the sample media of the presentdisclosure may be utilized in the test areas described inPCT/US2013/032603.

Additional Embodiments

Reference will now be made to more specific embodiments of the presentdisclosure. However, Applicant notes that the disclosure below is forillustrative purposes only and is not intended to limit the scope of theclaimed subject matter in any way.

Example 1. Fabrication of Zinc Impregnated Sample Media

This example illustrates impregnation of zinc (Zn) on a sample medium.Various methods can be used to impregnate the Zn into a sample medium.The even, thorough and uniform distribution of Zn on a sample medium isan important factor for facilitating its consistent reaction withsubstances.

One way of impregnating zinc onto a sample medium is to mix it in asolvent while continually agitating it to keep the metal particlessuspended. This suspension can then be applied to the sample medium.Methods to achieve this can be dipping the medium in the suspension,dripping the suspension, or spraying the suspension onto the medium. Thefirst two methods are preferred as spraying a suspension with metalparticles can be problematic due to the potential clogging of thesprayer.

A suspension of 0.25% Zn and ethanol (EtOH) was made by mixing 0.2 g ofZn with 79.1 g of EtOH to produce the metal suspension. 10 uL of thesuspension was dispensed on the sample medium area (i.e., a porousfilter paper) to form a uniform circle of aqueous suspension. Next, EtOHor other solvents were allowed to evaporate for 2-3 minutes, therebyleaving impregnated Zn on the sample medium.

The uniformity of the impregnated Zn on the medium is dependent on theflow and the coverage of the suspension. Rapid flow of the suspensionthroughout the target sample medium is optimal, as it distributes the Znbefore it has a chance to settle out of the suspension.

With the test medium now impregnated with the metal, chemicalsintroduced to the medium will now utilize the presence of the metal toimplement the colorimetric reaction to detect the presence of thesubstance under question.

Example 2. Detection of Substances

This example illustrates a specific method of utilizing flexible cardcomponent 12 (FIGS. 1A-B) and chemical detection unit 100 (FIG. 3) todetect an unknown substance by utilizing a sample medium that isimpregnated with a solid test chemical (e.g., the zinc impregnatedsample medium from Example 1). Pad 10 on flexible card component 12represents a sample medium that is impregnated with a solid testchemical. Pad 10 is in fluid communication with reagent releasablecapsules 18 of flexible card component 12 (FIG. 1C). In operation, pad10 is swiped onto a surface of interest that is suspected of containinga substance. Next, a reaction between the substance and solid testchemical on the pad 10 is initiated by coupling flexible card component12 with chemical detection unit 100 through opening 30. The coupling offlexible card component 12 with chemical detection unit 100 causes wallsof reagent releasable capsules 18 to yield to fluid flow to establishfluid communication between liquid reagents in reagent releasablecapsules 18 and pad 10. This can happen by a disruption of the walls ofthe reagent releasable capsules 18 upon the coupling of pad 10 withchemical detection unit 100.

The arrival of the liquid reagents from reagent releasable capsules 18onto pad 10 results in the reaction of the solid test chemical with thesubstance. This in turn leads to the generation of a color.

The generated color is then matched to a known substance by comparingthe generated color characteristics utilizing a color algorithm. Thisalgorithm may assess the color magnitude or intensity, rate of colorchange, decreasing color change and timing of the various color changesor combinations thereof. This results in the detection and/oridentification of the substance.

Without further elaboration, it is believed that one skilled in the artcan, using the description herein, utilize the present disclosure to itsfullest extent. The embodiments described herein are to be construed asillustrative and not as constraining the remainder of the disclosure inany way whatsoever. While the embodiments have been shown and described,many variations and modifications thereof can be made by one skilled inthe art without departing from the spirit and teachings of theinvention. Accordingly, the scope of protection is not limited by thedescription set out above, but is only limited by the claims, includingall equivalents of the subject matter of the claims. The disclosures ofall patents, patent applications and publications cited herein arehereby incorporated herein by reference, to the extent that they provideprocedural or other details consistent with and supplementary to thoseset forth herein.

What is claimed is:
 1. A method of making an assembly, said methodcomprising: combining a sample medium with a solid test chemical,wherein the solid test chemical comprises zinc, and wherein the solidtest chemical becomes dispersed uniformly on a surface of the samplemedium.
 2. The method of claim 1, wherein the combining occurs by:suspending the solid test chemical in a solvent to form a suspension;and combining the suspension and the sample medium.
 3. The method ofclaim 2, wherein the combining occurs by spraying the suspension ontothe sample medium.
 4. The method of claim 2, wherein the combiningoccurs by dropping the suspension onto the sample medium.
 5. The methodof claim 2, wherein the combining occurs by soaking the sample mediumwith the solid test chemical.
 6. The method of claim 2, wherein thecombining occurs by introduction of the solid test chemical to thesample medium.
 7. The method of claim 2, wherein the solvent is selectedfrom the group consisting of ethanol, methanol, water, organic solvents,and combinations thereof.
 8. The method of claim 2, wherein the solventis ethanol.
 9. The method of claim 1, wherein the combining occurs byintroduction of the solid test chemical to the sample medium without theuse of a solvent.
 10. The method of claim 1, wherein the combiningoccurs by spraying the solid test chemical on the sample medium.
 11. Themethod of claim 1, wherein the combining occurs by electrostaticdeposition of the solid test chemical on the sample medium.
 12. Themethod of claim 1, wherein the combining occurs by vacuum deposition ofthe solid test chemical on the sample medium.
 13. The method of claim 1,wherein the solid test chemical becomes dispersed uniformly on a surfaceof the sample medium.
 14. The method of claim 1, wherein the solid testchemical becomes specifically dispersed.
 15. The method of claim 2,wherein the solvent is allowed to evaporate.
 16. The method of claim 1,wherein the solid test chemical further comprises a component selectedfrom the group consisting of metals, transition metals, metalloids, andcombinations thereof.
 17. The method of claim 1, wherein the samplemedium is selected from the group consisting of filter papers, poroussheets of fibers, porous papers, and combinations thereof.
 18. Themethod of claim 1, wherein the sample medium is selected from the groupconsisting of adhesives, plastics, gels, and combinations thereof. 19.The method of claim 1, wherein the assembly is capable of detecting asubstance comprising an inorganic nitrate.
 20. The method of claim 19,wherein the zinc combined with the sample medium reacts with theinorganic nitrate to produce nitrite ions that react with at least oneliquid reagent to produce a colored azo dye, wherein the colorcorresponds to the substance.
 21. The method of claim 1, wherein thesample medium comprises a pad of a flexible card component.
 22. Themethod of claim 21, wherein the flexible card component comprises atleast one liquid reagent in at least one reagent releasable vessel. 23.The method of claim 1, further comprising a step of associating thesample medium with at least one reagent releasable capsule, wherein theat least one reagent releasable capsule is operable to be in fluidcommunication with the sample medium, wherein the at least one reagentreleasable capsule comprises at least one liquid reagent, wherein thesample medium is configured to collect a substance thereon, and whereinthe zinc combined with the sample medium is configured to react with aninorganic nitrate in the substance to produce nitrite ions that reactwith at the least one liquid reagent to produce a colored azo dye whenfluid communication is established between the at least one liquidreagent in the at least one reagent releasable capsule and the samplemedium.